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Abstract: PO2264

Cell-Based C5b9-ELISA to Identify Patients with Atypical Hemolytic Uremic Syndrome

Session Information

Category: Pathology and Lab Medicine

  • 1602 Pathology and Lab Medicine: Clinical

Authors

  • Reinhardt, Martin, Medizinische Hochschule Hannover Zentrum Innere Medizin, Hannover, Niedersachsen, Germany
  • Haller, Hermann G., Medizinische Hochschule Hannover Zentrum Innere Medizin, Hannover, Niedersachsen, Germany
  • Kiyan, Yulia, Medizinische Hochschule Hannover Zentrum Innere Medizin, Hannover, Niedersachsen, Germany
Background

Discrimination between different diseases in patients suffering from thrombotic microangiopathies is often challenging. Measuring C5b9 deposit on endothelial cells using confocal microscopy have been shown to be convenient in diagnostic and therapy monitoring of Atypical hemolytic uremic syndrome (aHUS) but methods are complex and costly.

Methods

We developed a cell-based C5b9-ELISA to measure C5b9-deposits on activated endothelial cells. Patients with suspected aHUS and other thrombotic microangiopathies were identified in early disease stage. Serum was drawn and tested versus healthy controls. After confirmation of the diagnosis aHUS therapy efficiency was monitored using the assay.

Results

In patients with the clinical diagnosis of aHUS we were able to show up to six-fold higher C5b9-deposits in contrast to normalized human serum (NHS) (p-value < 0,0001). In comparison to healthy controls, patients suffering from either Shiga-Toxin-HUS or Thrombotic Thrombocytopenic Purpura (TTP) we could demonstrate a two- to three-fold higher deposit (p-value=0.0103 and below). After onset of eculizumab treatment, the amount of C5b9-deposits becomes lower than in healthy controls, proving the efficiency of the therapy. One-Way-ANOVA shows significant differences between aHUS-groups and controls, but not between aHUS patients using Tukeys-multiple comparisons test.

Conclusion

We described a novel, fast and reproducible ELISA to identify aHUS-patients by measuring C5b9-deposits and monitor disease activity. This can give a rise to diagnostic speed and therapy decisions. Further investigation and validation are needed to show interactions with other complement diseases like systemic lupus erythematosus.

ELISA-results with 95 % CI. A: C5b9-deposits in different patients. B: C5b9-deposits before and after two doses of eculizumab in patient 2 compared to healthy control 1.